Wireless local area networks are used in various applications instead of wired connections. One example is mobile phones and other mobile devices. These devices have become very popular and thus, wireless networks are widely provided. Many mobile device users prefer wireless local area networks instead of mobile communications, such as 3G- or LTE networks because wireless local area networks are typically capable of providing higher transfer rate and many times they are provided free of charge while mobile communications are often bound by additional costs. A known problem of wireless local area networks is that they do not hand moving mobile station as well as mobile communication networks, which are designed with particular standardized hand-over functionality. In other words, they are often the preferred choice when the user of the mobile device does not move but needs high bandwidth in data transfer.
Even if wireless local area networks work generally quite well there is a plurality of special cases that require special purpose solutions. For example, providing a network connection in a fast train or car includes problems relating to high speed and lack of wired cables. The present application addresses corresponding problems in the field of elevators. An elevator includes special features as it moves in an elevator shaft and never leaves it. When the building is not high it is possible to provide just an ordinary wireless local area router, or a base station, to which mobile devices can connect. The coverage of a wireless local area network base station depends on various aspects, however, it is not typically more than 50 meters in an urban environment and in most cases it is lot less than 20 meters. In addition to the long distance the elevators move fast in high buildings and this causes further problems.
When the building gets higher it means that the coverage area of the router must be increased. This is typically done by increasing power, which leads into a plurality of problems. When the power of the router is increased more and more mobile stations try to connect to it and it might suffocate under the burden of requests. In very high buildings the need for power increase might be more than the mobile devices are capable of. In other words, even if the transmitting power of the router may be increased in order to transmit to mobile stations, the mobile stations might not be powerful enough to respond and the communication is not successful.
Further problems for conventional routers are caused by, for example, the Doppler effect of moving elevator car, multipath propagation in the elevator shaft, metallic structures and walls in the and similar commonly known problems.
Thus, it is obvious that the conventional wireless local area network arrangement have drawbacks particularly in providing high quality service in high building comprising fast moving elevators. Thus, there is a need for providing enhanced solutions for data transfer in elevators.
Conventionally data and telecommunications in an elevator system have been arranged by using a wired connection, however the cables suitable for high speed data transfer, particularly optical fibers, are not suitable to be used together with an elevator rope because of their properties. Furthermore, the wired connection involves an additional weight. A problem of the additional weight is that moving it requires energy and stronger supporting structures. Thus, any additional weight needs to be avoided whenever it is possible. Furthermore, if the wire is broken the reparation process might not be easy. Thus, there is a plurality of drawbacks in using wired communications in an elevator.